Locking lamp



July 29, 1930. H, HUBBELL 1,771,631

LOCKING LAMP Filed Aug. 50, 1926 k i ii .1:- Q i i Patented 1.1, 29, 1930 UNITED STATES PATENT, Orr-Ice HARVEY HUBBELL, OF BBIDGEPOR'I, CONNECTICUT; LOUIE E. HUBBELL EXECUTE]! OF SAID HARVEY HUIBBELL, DECEASED LOCKING LAMP Application filed August 30, 1926. Serial No. 132,437.

This invention relates to electric lamps, and has for its general object to provide an improved and simplified construction for a lamp which may be readily attached to a lamp socket, but which when in place can not be removed from the socket without rendering the lamp useless, to thus discourage theft and changing of lamps by unauthorized persons.

It is old in electric lamps to so construct the lamp base that it cannot be removed from the socket without breaking one of the connections from the terminals to the filament. This type of lamp, however, is unreliable because there is no positive assurance that the connection will be broken since this connection may stretch or yield, or due to inaccuracies of manufacturers may be so long that the relative movement between the elements on the base which is depended upon to break contacts within the lamp socket, but instrumentalities were provided which operated upon and by the operation of removing the lamp from the socket to positively move one of the terminals to a. position where it could not engage the contact within the socket, with additional means to prevent return of this terminal to its original position, so that after the lamp was once-removed from the socket it was useless. Thus the lamp was so constructed that it could be placed in an ordinary lamp socket but could not be unscrewed therefrom without first performing an operation which destroyed the usefulness of the lamp.

The present invention relates to a construction of the type illustrated in said patent in which, instead of relying on the breaking of the connection to one of the terminals to render the lamp useless, one of the terminals is shifted so that it cannot engage its contact in the lamp socket, and it is an object of the 'vide a device which may be inserted in the socket with practically the same ease as an ordinary lamp, but will have a device posi-' tively operated by a reverse movement of the lamp toprevent its removal from the socket unless it is so manipulated as to dost-r0 its usefulness, and it is a further object of the invention to provide a structure in which should the bulb be broken the base may still be easily removed from the socket.

VV1th the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing, in which a Fig. 1 is a side elevation of the uppeppart of an incandescent bulb showing my .improved base in elevation.

Fig. 2 is a vertical section on an enlarged scale through the base and a lamp socket showing the elements in the normal operative position, the upper portion of the bulb being shown in elevation.

Fig. 3 is a transverse section substantially on line 3-3 of Fig. 2, butomitting the lamp socket. 4 P

Fig. 4 is a similar view showing the base removed from the socket and showing the position of the elements to which they have been shifted by the act of removing the'bulb from the socket so as to render it useless.

F g. 5 is a transverse section substantially on line 5-5 of Fig. 4.

Fig. 6 is an end view of the lamp base with a portion broken away to more clearly show the operation of the device provided to pre vent removal of the bulb from the socket without first destroying the usefulness of the bulb, and

Fig. 7 is a detail side elevation of the upper end of the insulating body member taken at right angles to the planes of Figs. '1 and 3.

The lamp comprises the usual glass bulb 10 of any desired shape enclosing any suitable filament, not shown. Mounted on this bulb is the base which comprises an insulatmg body or cup member 11 which is open at its lower end to rovide a chamber 12 to' receive the end 0 the bulb, and in which is laced a suitable cement 13 to secure the dy member to the bulb. The body member is generally circular in cross section and;

- ment is small so that the terminal will turn with the body member except for this small relative movement. The body member is provided wih a longitudinally extending groove 15 in the outer side wall thereof into which projects a key member 16 rigidly secured to the screw shell. This key is preferabl secured by projections 17 on one side whic extend through openings in the shell and are riveted over, as shown. The groove 15 is of greater width than the key to allow for the small relative turning movement above mentioned, and which is rovided for a purpose presently to be descri (1. At its lower portion the groove 15 preferably passes through the body member to the chamber 12 to provide an o ening for the convenient assage of one of the connections 18 from the lament to the screw shell 14 to which it is attached b any suitable means, such as solder, as indlcated at 19.

At its u per end the cup or body member is rovide with a recess 20 which 1s non-circu er in cross section, preferably substantially square, and there is also an opening 21 from the chamber 12 to this recess which, however, is of such a size as to leave a shoulder 22 at the top of the chamber. As shown in Figs. 1 and 2, the screw shell terminal 14 normally encloses the greater portion of the upper part of the cup or body and has an mwardly extending top ortion 23 which rests against the end of the dy. Thls to has an opening therein substantially of t e same size and shape as the recess 20 1n the body for the passage of a similarly shaped extension 24 on an insulating button 25 whlch forms a sup ort for the central or end terminal 26. shown in the drawing, the opening in the top 23 does not closely fit the extension 24 but is somewhat larger than this extension to permit a limited turning movement of the terminal 14 on the bod member for a purposev which will be described later. The body of the button is larger thanthe extension so as to form a shoulder to rest on the top 23 of the screw shell terminal. The button 25 is provided at its opposite ends with recesses 27 and 28 connected by a restricted passage or opening 29.

The end terminal 26 has a series of laterally extending lugs or cars 30 which normally rest on the top of the button, as shown in Figs. 2 and 6, and retain this terminal 1n thls pos tion. A tubular rivet 31 is connected to this terminal and passes through the opening 29 into the lower recess .28 where it is flared and prevent separation thereof should the sleeve be moved downwardly. The other lead or connection 35 from the filament passes through the sleeve 33 and the tubular rivet 31 to the end terminal 26 and is connected gleretoby any suitable means, such as solder The upper portion of the cup or body member 11 is reduced somewhat in diameter, as shown at 37, to provide space for a flat spring 38; This spring is preferably made of a strip of flat metal and is secured to the inner side of the screw shell terminal 14by the upper projection 17 on the key 16 which passes through this spring. Thls projection passes through the spring intermediate the ends thereof so the opposite ends of the spring are free, and it is so shaped that they tend to move inwardly away from the wall of the screw shell under the resilient action of the metal. At its upper end the body 11 is provided with transverse recesses 39 on opposite sides to form shoulders 40 to cooperate with these springs in a manner presently to be described. Adjacent one end the spring is bent inwardly and then outwardly to form a curved cam portion 41, and the free end 42 of the spring normally asses through an opening 43 in the side wall of the screw shell 14 to engage the inner surface of the screw contact 44 in the lamp socket 45. This free end is preferably somewhat pointed and also is provided with a notch 46 to give sharp points to more positively gri the inner surface of the screw contact. T e outer wall of the cup or body member 11 is provided with an upright notch or groove 47 which is normally under the cam portion 41 of the spring so that this portion can extend into this notch or groove. It thus allows the free end 42 of y the spring to retract somewhat, as shown in Fig. 3, so that it normally projects only a slight distance beyond the outer surface of the screw shell 14.

The operation is as follows: The positions of the elements forming the base of the lamp are normally that shown in Figs. 1, 2 and 3, and in this condition the lamp may be screwed into the standard lamp socket the same as the ordinary lamp. Durin this operation of screwing the lamp into t e socket turning movement to the right or clockwise on the bulb and the body member 11 will maintain Hill 15 i interfere with the turning movementof the the elements in the positions shown in Fig. 3 with the lower wall or shoulder 48 of the groove in the body engaging the key 16, and will, therefore, rotate the screw shell contact 14 with the body member. The insulating button or support 25 for the end terminal 26 will also rotate with the body member be cause of the squared extension 24 extending into the recess in the body and thus there will be no tendency to twist off the electrical connection 35. In this position the notch or groove 47 in the side of the body member is 1n alignment with the cam portion 41 of the spring and allows the free end of the spring to be retracted inwardly so that it does not screw shell. Of course, when the lamp is in position in the socket the end terminal 26 engages the central contact 49 in the lamp socket in the usual manner. Should now a thiefor other person attempt to remove the lamp from the socket he will, of course, turn the bulb in the op ,osite direction or counterclockwise. The 'rst effect of this movement is to turn the insulating body member 11 a slight distance relative to the screw shell 14 because this shell is held by engagement with the screw contact 44 in the lamp socket and the groove 15 in the body is wider than the key 16. This brings the elements to the position shown in Fig. 6 with the upper shoulder of the wall 50 of the groove 15 against the key 16. It also shifts the side of the notch 47 against the cam portion 41 of the spring and by a camming action thereon forces the free end 42 of the spring outwardly and clamps it tightly against the inner surface of the screw contact 44'of the socket. This end of the spring is also inclined relative to this surface, as indicated, so that a continued attempt to turn the lamp in this direction will more tightly force the end of the spring against this contact. The spring will, therefore, tightly grip the inner surface of the screw contact 44 and will lock the lamp in the socket and thus prevent its removal from the socket. It will be noted that by use of the camming action of the side of the notch 47 with the curve of the spring I may use a heavier spring, because in normal operation of screwing the lamp into the socket the spring does not engage the surface of the screw contact of the socket with suiiicient pressure to interfere with this operation. I also secure a positive lock between the base of the lamp and the socket because of this camming action. I, therefore, am not required to rely on the resiliency of the spring to secure this locking eflect.

The lamp, however, may be easily removed from the socket, but not without destroying I its usefulness. To do this-it is simply first necessary to pull downwardly or outwardly away from the socket on the bulb 10 or the insulating body 11. This will shift the insulating body 11 downwardly or lon itudinally relative to the screw shell termina 14 which, of course, will be held b the screw contact 44 in the socket. The e ements are now in the positions shown in Figs. 4 and 5. During this longitudinal movement of the body member the connection between the sleeve 33 and the tubular member 31 has drawn the end terminal 26 into the recess 27 To permit this movement the lugs or ears 30 are made to yield upwardly undermz certain strain, and after the terminal has once been shifted into the recess the resilient action of the metal will cause the ends of these lugs to grip the side walls of the recess so that it will require considerable force to move the terminal back to its original position. This terminal is now, therefore, in a position where it cannot' engage the central lamp contact 49 in the socket, and therefore, the lamp is useless. This movement of the body member relative to the screw shell terminal will also in all probability break the connection 18 from the filament to the screw shell terminal, especially as the upper edge 51 of the opening through the body for this connection may engage the upper side thereof. This is another feature which increases the probability of rendering the lamp useless, ut it will, of course, be understood that the main reliance is placed on the shifting of the end terminal 26 to a position where it cannot engage the central contact in the socket. It is also to be noted that shifting of the end terminal is accomplished without the necessity of breaking the connection 35 to the filament, and therefore, it is not necessary to break either connection from the filament to render the lamp useless.

After this longitudinal movement of the insulating bod member 11 with respect to the screw shel terminal 14 it is impossible to return the elements to their original positions. When the body has reached the end of its movement the free end portions of the spring 38 are no longer held by the side walls of the body member, and therefore, they spring inwardly over the top of the shoulders 40. They, therefore, engage these shoulders to prevent return of the body member to its original position, and as they are enclosed by the screw shell they are inaccessible and cannot be forced outwardly to permit this return movement. Should they by some means he moved out of the path of movement of the shoulders 40, inward movement of the body member would not return the end terminal 26 to its original position because of the sliding connection between the Sleeve 33 and the tubular member 31. In other words a reverse movement of the body member would merely slide the sleeve 33 along the tubular member 31 without in any way shifting the end terminal.

The key 16 is of a sufficient lgngth so that a part of it is always in the groove 15, and therefore, will always form a ositive connection between the-screw shel terminal 14 and the insulatin body member 11. The extension" 24 on tile button 25 is of such a length that it extends into the non-circular recess 20 of the body so that this button also always turns with the body member. It will, of course, be apparent that, when the free ends of the spring 38 swing inwardly over the top or shoulders 40 of the body member when this member is shifted longitudinally with respect to the screw shell terminal, the locking end 42 of the spring moves into the screw shellaway from the surface of the screw contact 44 of the socket and it, therefore, no longer has any locking effect. The lamp base is, therefore, now unlocked and may be easily removed from the socket by merely unscrewing it the same as any lamp.

It will be noted that the insulating body member 11 projects below or-outwardly of the entrance to the lamp socket, as indicated in Fig. 2, and is provided with a circular wall 52 by which the body may be gripped to facilitate its removal from the socket. Thus should the bulb become broken the base may still be easily removed from the socket because of the extension 52 of the body to a position where it may be grasped by the operator for this purpose. I

It will be apparent from the foregoing description that I have devised alocking lamp structure which is very simple in construction involving a small number of parts which are all thoroughly insulated. It will also be apparent that all of the elements are positive in operation so that normally the lamp is securely locked in the socket. It may, however, be easily unlocked and removed, but not without positivel destroying the usefulness of the lamp an so placing 1t in such condition that the elements cannot be returned to their ori ina'l positions.

aving thus set forth the nature of my invention, what I claim is:

1. An electric lamp comprising a bulb, an insulatin body member secured to said bulb, a screw 5 ell terminal carried by said body and mounted to turn with the body and for,

lon itudinal movement thereon, an insulating utton mounted on the shell and having a non-circular extension projecting into a similarly sha ed recess in the body so as to turn with the ody, an endterminal carried by the button in position to engage a lamp socket contact and movable to a position in the button away from said contact, and a connection from said body to said contact to shift said contact by relative longitudinal movement of the shell and body.

2. An electric lamp comprising a bulb, an

insulating body member secured to said bulb,

a screw shell terminal carried by said body and mounted to turn with the body and for longitudinal movement thereon, an insulating button mounted on the shell and having anon-circular extension r 'ecting into a similarl sha ed recess in 51c ody so as to turn wit the body, an end terminal carried by the button in osition to engage a lamp socket contact and movable to a position in the button away from said contact, a connection from said body to said contact to shift said contact by relative longitudinal movement of the shell and body, and automatically operating means to prevent return of the members to their original positions.

3. An electric lamp com rising a bulb for a filament, an insulating ody member secured to said bulb, a screw shell terminal mounted on said body member for relative longitudinal movement upon removal of the lamp from the socket, cooperating means on the shell and bod to cause the shell to turn with the body in 0th directions, an insulating support mounted on said shell, an end terminal mounted on said support to engage a lamp socket contact, connections from said terminals to the filament, and a direct connection extending from the body to the end terminal capable of moving said terminal into the support but incapable of moving it out.

4:. An electric lamp com risin a bulb, a screw shell terminal, an insu ating ody member longitudinally movable in said terminal and secured to said bulb, said body member being provided with a hand grip to extend from a lamp socket, oooperatin means on the shell and body to cause the she I to turn with the body in both directions, an insulatin button carried by said terminal and provide with an opening, an end terminal carried by said button in position to engage a contact in a lamp socket, and a connection from the body member to said end terminal so that it will be drawn into said opening away from the contact by longitudinal movement of the body member, and means to prevent return of the body to its original position.

- 5.. An electric lamp comprising a bulb, a screw shell terminal, an insulating body member longitudinally movable in said terminal and secured to said bulb, an insulating button carried by said terminal and provided with an opening, an end terminal carried by the button at the outer end of said opening, and means connecting the end terminal with said body to draw the terminal into-the opening upon said longitudinal movement and including a lost motion connection incapable of moving the terminal to its original position.

screw shell termina an insulating body member longitudinally movable in said terminal and secured to said bulb, an insulating button carried by said terminal and provided with an opening, an end terminal carried by the button at the outer end of said 6. An electric lam comprising a bulb, a

opening, and a connection from the end terminal to said body member comprising a tubular element and a sleeve connected to A adapted for attachment to a lamp socket, an

end terminal in position to engage a contact in a lamp socket and insulated from said shell, an insulating body member longitudinally movable in said shell and secured to said bulb, means operatively connecting said body and shell for rotation together in opposite directions in all positions of said body for. securing the lamp to or removing it from the lamp socket, and means operable by longitudinal movement of the body member to move the end terminal to a position Where it cannot beengaged by its socket contact.

8. An electric lamp comprising a bulb and a lamp base, said lamp base including a shell adapted for attachment to a lamp socket, an end terminal in position to engage a contact in a lamp socket and insulated from said shell, an insulating body member longitudinally movable in said shell and secured to said bulb, means operatively connecting said body and shell for rotation together in opposite directions in all positions of said body for securing the lamp to or removing it from the lamp socket, means operable by longitu dinal movement of the body member to move the end terminal toaposition where it cannot be engaged by its socket contact, and means to prevent longitudinal movement of the body member in the opposite direction to prevent return of the end terminal to its original position.

9. An electric lamp comprising a bulb and a lamp base, said base including a shell adapted for attachment to a lamp socket, an insulating body member longitudinally movable in the shell and secured to said bulb, said body being provided with a hand grip to eX- tend from a lamp socket, means operatively connecting said shell and body member to .Cause them to rotate together at each extreme of the longitudinal movement of the body member to permit the lamp to be secured in or removed from the lamp socket, a

spring secured to said shell and arranged to engage the socket to prevent removal of the shell therefrom, said body having means to hold the spring in efleetive holding position when the shell and body are in lamp securing position and to release the spring when the shell and body are in lamp removing position, an insulating button carried by the shell and having an opening therein, an end terminal carried by said button in position to engage a contact in the lamp socket, and means connecting the terminal to the body member to draw the terminal into the opening on longitudinal movement of the body, said spring being arranged to move into alignment with the end of the body after this longitudinal movement to prevent its return '0 to the original position.

10. An electric lamp comprising a bulb and a lamp base' includin' a shell and an insulating body member a apted ior relative longitudinal movement, said body member having a hand grip to project from a lam socket, the body being secured to the bulb and the shell being mounted to turn with the body in both directions and adapted for attachment to a lamp socket, an insulating butgo ton carried by the shell and having an opening'therein, an end terminal carried by said" button in position to engage a contact in the lamp socket, a positive connection from the body to the terminal to draw the terminal 5 into the opening away from its contact by longitudinal movement of the body upon manipulation of the bulb to remove it from the socket, and means to prevent return of the terminal to its original position.

11. An electric lamp comprising a bulb and a lamp base including a shell and an insulating body member adapted for relative movement, the body member being socured to the bulb and provided with a longitudinal groove, the shell being adapted for attachment to a lamp socket, a key on the shell extending into the groove, an insulating button carried by the shell and having an opening therein, an end terminal carried by the button in position to engage a contact in the lamp socket, a positive connection from the terminal to the body member to draw said terminal into the opening away from its contact-by manipulation of the bulb to remove it from the socket, and automatically operable means to prevent return of the terminal to its original position.

12. An electric lamp comprising a bulb, a screw shell terminal, an insulating body member in said terminal and movable longitudinally thereof, said body being connected to the bulb, coacting means carried by the shell and body to cause them to-rotate together comprising a longitudinal groove in the body and a key carried by the shell projecting into said groove, an insulating button carried by the shell and provided with a recess, an end terminal carried by the button, a connection from the end terminal to said body to draw the terminal into the recess by said longitudinal movement of the body, and a spring secured to the shell and arranged to move to a position between the end of the body and the shell after said movement to prevent return of the body to its original position. I

13. An electric lamp comprising a bulb, a screw shell termfiiah an insulating body connected to the bulb and extendi gi to he 14. An electric lamp comprising a bulb, a'

screw shell terminal adapted for connection to a lamp socket contact, an insulating body member secured to the bulb and. extending into the shell, said body being ada ted for longitudinal movement relative to t e shell, coacting means carried by the shell and body to permit limited relative turning movement of the shell and body, locking means carried by the shell to engage said lamp socket contact to prevent removal of the shell, and means operable by said relative turning movement to clamp said locking means against the contact.

15. An electric lamp comprising a bulb, a

screw shell terminal adapted for connection to a lamp socket contact, an insulating body member secured to the bulb and extending into the shell, coacting means on the shell and body to-permit limited relative turning movement between the shell and body, locking means carried by one of said members to engage said socket contact to prevent removal of the shell from the socket, and means operable by said relative turning movement to shift said locking means to holding position.

16. An electric lamp comprising a bulb, a screw shell terminal adapted for connection to a lamp socket contact, an insulating body member secured to the bulb and extending into the shell, said body being ada ted for longitudinal movement relative to t e shell, coacting means carried by the shell and body to permit limited relative turning movement of the shell and body, an insulating button carried by the shell having a recess, an end terminal carried by said button in position to engage a central lamp contact, a connection from the end terminal to said'body to draw said terminal into the recess by said longi tudinal movement, coacting means on the body to its original position and to release to a lamp socket contact, an insulating body member in said shell and mounted for relative longitudinal movement, coacting means carried by the shell and body to cause the shell to turn with the body, locking means to prevent removal of the lamp from the socket, means operable by said longitudinal movement to render the lamp inoperative and to release said locking means, and said body being provided with an extension outside the socket to form a grip for manipulation of said body and removal of the shell from the socket.

18. An electric lamp comprising a bulb, a base for said bulb including a screw shell to engage the screw contact of a lamp socket, means for connecting the bulb to the shell arranged to allow limited relative turning movement in both directions between the shell and bulb, a locking means for locking the shell to the socket and normally out of locking position, and means operated by said limited relative turning movement to shift said locking means to a position to lock the shell to the socket.

19. An electric lamp comprising a bulb, a screw shell terminal adapted for connection to a lamp socket, a bulb connected to the shell and mounted for longitudinal movement relative to the shell, coacting means between the shell and bulb to permit limited turning movement between the shell and bulb, looking means capable of locking the shell to the socket .and normally out of locking osition, means operable by said limited relative turning movement to shift said locking means to a position to lock the shell to the socket, and means operable by said relative lon 'tudinal movement of the bulb to release sai locking means.

In testimony whereof I aflix m signature.

' HARVEY BELL.

shell and body to permit limited relative turning movement between the shell and body, a locking spring carried by the shell and arranged to engage the lamp socket contact to prevent removal of the lamp from the socket, and coacting means carried by the body and spring operable by said turning movement to press the spring against the contact, said spring being arranged to move to a position between the shell and body after said lon tudinal movement to prevent return of t e 

